The present invention relates to a coupling, and more particularly to a coupling for securing a handlebar to a bicycle frame.
As shown in FIG. 4, a conventional coupling for securing a handlebar to a bicycle frame comprises a washer W provided between a compression nut N and a bowl B, and a ball bearing A disposed in a bowl B. In order to maintain a good operational capability for the bearing A and to avoid a permeation of water into the bearing A, a sealing ring S is provided in an upper portion of the compression nut N. The sealing ring S has generally an O shaped cross section or a rectangular cross section. The sealing ring S is disposed in a groove formed in the compression nut N without support before a standpipe P can be inserted downward into the compression nut N.
The inner diameter of the sealing ring S is smaller than an outer diameter of a standpipe P so as to make a water tight seal between the standpipe P and the compression nut N. Obviously, the standpipe P contacts and hits the sealing ring S before it can be inserted into the compression nut N. This causes problems during assembling processes. It may take several times for an assembler to insert the standpipe P into the compression nut N so that the sealing ring S is retained in position.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional sealing ring.